AwardEmoji: Validate custom emoji as valid name

When validating award emoji, a custom emoji name is also valid.

app/validators/gitlab/emoji_name_validator.rb

@@ -11,9 +11,24 @@
 module Gitlab
   class EmojiNameValidator < ActiveModel::EachValidator
     def validate_each(record, attribute, value)
-      unless TanukiEmoji.find_by_alpha_code(value.to_s)
-        record.errors.add(attribute, (options[:message] || 'is not a valid emoji name'))
-      end
+      return if valid_tanuki_emoji?(value)
+      return if valid_custom_emoji?(record, value)
+
+      record.errors.add(attribute, (options[:message] || 'is not a valid emoji name'))
+    end
+
+    private
+
+    def valid_tanuki_emoji?(value)
+      TanukiEmoji.find_by_alpha_code(value.to_s)
+    end
+
+    def valid_custom_emoji?(record, value)
+      namespace = record.try(:awardable).try(:namespace)
+
+      return unless namespace
+
+      namespace.custom_emoji&.by_name(value.to_s)&.any?
     end
   end
 end

spec/models/award_emoji_spec.rb

@@ -58,6 +58,19 @@ RSpec.describe AwardEmoji do
         end
       end
     end
+
+    it 'accepts custom emoji' do
+      user  = create(:user)
+      group = create(:group)
+      group.add_maintainer(user)
+
+      project = create(:project, namespace: group)
+      issue = create(:issue, project: project)
+      emoji = create(:custom_emoji, name: 'partyparrot', namespace: group)
+      new_award = build(:award_emoji, user: user, awardable: issue, name: emoji.name)
+
+      expect(new_award).to be_valid
+    end
   end
 
   describe 'scopes' do